I have configured opnvpn on a Yealink phone a while ago... not to opnsense but a cloud vpn.What type of phone and firmware version are you using. I remember that the format can depend from phone to phone and version to version...

Try renaming your files using this naming convention and folder layout. It is very picky about the filenames and folders.

cd clientconf# from within the clientconfdirectory:tar -c vpn.cnf keys/* -f openvpn.tarYou need to run the tar command from within the folder itself. Otherwise the paths will get mangled and the file won't work.Upload that file in the Web GUI or via your provisioning system.

This makes me happy. We successfully use Yealink phones in a particular setup, but over a heavier IPsec VPN where each branch has a dedicated tunnel to the main office, but this seems a lot simpler as the phones could be deployed as is.